Endothelium-Dependent Hyperpolarization To Acetylcholine In Rabbit Pulmonary Artery

In 1980, Furchgott and his colleagues presented the first evidence that acetylcholine (ACh), by acting on the endothelial cells, stimulated the release of a relaxing factor (EDRF) that acted on the preconstricted rabbit thoracic aorta to produce relaxation. A research interest on the regulatory function of vascular endothelium, since then, is on the increase, and now the biological and chemical evidences have been obtained to show that EDRF is nitric oxide (NO). In addition to ACh, a large number of agents such as histamine, serotonin, bradykinin, ATP and ADP are also shown to stimulate the release of EDRF.The question remained: are there other such factors released from vascular endothelium? The answer is that this is indeed the case. In the later of 80's, the results obtained in Weston and Suzuki's laboratories and other laboratories showed that a new substance, christened EDHF, could be released by ACh and other agents, and the EDHF could cause hyperpolarization of the smooth muscle cells of arteries. As a new endogenous regulatory factor from endothelium, however, the mechanism and the significance of its action have not been fully understood. The objectives of this study were: (1) to clarify the role of NO in ACh-induced endothelium-...